Add Advanced cluster architecture diagram (#20160)

* Add Advanced cluster architecture diagram

* Upload Omnigraffle file for future edits

* Reword plane introduction

* Comments from Mike

* De-planeing diagram description

* Devarshi feedback

Author: jhlodin

src/current/cockroachcloud/plan-your-cluster-advanced.md

@@ -12,6 +12,17 @@ This page describes how to plan your CockroachDB {{ site.data.products.advanced
 
 Before making any changes to your cluster's configuration, review these requirements and recommendations for CockroachDB {{ site.data.products.advanced }} clusters. We recommend that you test configuration changes carefully before applying them to production clusters.
 
+## {{ site.data.products.advanced}} cluster architecture
+
+The following diagram shows the internal architecture and network flow of a CockroachDB {{ site.data.products.advanced }} cluster:
+
+<img src="{{ 'images/cockroachcloud/advanced-architecture.png' | relative_url }}" alt="Diagram showing the architecture of Advanced plan Cloud deployments" style="border:1px solid #eee;max-width:100%" />
+
+CockroachDB {{ site.data.products.cloud }} operations are split into logical layers for **control** and **data**:
+
+- Control operations manage the CockroachDB cluster as a whole. These requests are handled by the **CockroachDB Cloud control plane** which communicates directly with cluster nodes as needed. These connections include access to the {{ site.data.products.cloud }} Console, DB Console, [Cloud API]({% link cockroachcloud/cloud-api.md %}), [observability features]({% link cockroachcloud/metrics.md %}), and other cluster management tools.
+- Data operations involve connections between data applications and your underlying CockroachDB nodes, including SQL queries and responses. Each region has a network load balancer (NLB) that handles and distributes requests across CockroachDB nodes within the region. {{ site.data.products.advanced }} clusters can utilize [private connectivity]({% link cockroachcloud/private-clusters.md %}) across the cloud to limit the amount of network traffic that is sent over the public Internet.
+
 ## Cluster topology
 
 ### Single-region clusters